What’s the purpose of lighting in a large city? That may seem like the a fine example of a stupid question, but it’s not. While we could answer that question with suggestions like safety, allowing for mercial hours and ease of travel, lighting may now be used as a way to collect data on private citizens.

Using bination of LEDs and big data technology, public lighting is the potential backbone of a system that could use billions of fixtures to collect data about traffic congestion at an intersection or a consumer walking down the cereal aisle, to name just a couple of applications.

What’s being called “intelligent environment” means lighting won’t simply be hardware but software, collecting data on everything from traffic congestion to gunshots to tracking a particular shopper in a grocery store.

Sensity Systems is a start-up that is already installing such lighting in places like Newark, NJ, Copenhagen and Bangalore, India. Cities all over the globe are looking to replace aging lighting systems, and LED “smart lights” peting for their business. Many find these “smart lights” attractive not simply because of their price tag, but for the information they glean.

G.E. has also been developing smart-shopping capabilities, working with m to employ a sort of GPS system that can give retailers a shopper’s location and orientation in a store within five centimeters of, say, a shelf or product display.

Companies are offering consumers selling points: receive an update on your smart phone as to where the closest parking spot is as you head to the mall, or (upon entering a store) get a coupon for an item you’ve bought in the past.

Not everyone is thrilled. The American Civil Liberties Union has stated strong opposition to this technology:

The creation of infrastructures for ubiquitous mass surveillance including the widespread deployment of lightbulb spying technology.Given the limited use of the product as a lighting device and the broad scope of its tracking and surveillance features, what this product really appears to be is a mass surveillance device being disguised as an LED light bulb.

Even those developing this technology admit there is more to consider than mere lighting.Sensity’s CFO Richard K. Reece states, “There’s a fine line between being helpful and being creepy.” Why do I have a feeling that creepy is going to win?